This invention relates generally to scanning electron beam scanners and more particularly to a method and apparatus for electron beam scanning.
Conventional scanning electron beam scanners, such as those used in computed tomography (CT) imaging systems, produce cross-sectional and three-dimensional (3D) images of the human body and objects such as baggage and cargo. The conventional scanning electron beam scanner includes a radiation source that is axially aligned with both a target and a detector. During operation, the radiation source emits radiation that impinges on the target. In response to this impingement, the target generates x-rays that are directed through the patient or object to the detector.
Moreover, conventional radiation therapy devices are often used to generate a high energy beam. The generated beam is typically axially aligned with the patient to receive the radiation treatment. More specifically, the conventional radiation therapy device includes a gantry which can be swiveled around a horizontal axis of rotation in the course of a therapeutic treatment. A treatment head (“collimator”) can be set at any angle (rotation on the z axis) of gantry directs a radiation beam along an axis toward a patient. The radiation beam is typically generated by a linear accelerator positioned within gantry. The radiation beam is trained on a treatment zone of the patient. The treatment zone is an area which includes the tumor for example to be treated.
It would be desirable to incorporate a conventional electron beam scanner into a system having a radiation therapy source. However, since the conventional therapy source is axially aligned with the treatment area, and the radiation source used in the conventional scanning electron beam scanner is axially aligned with both the target and the detector, the conventional scanning electron beam scanner cannot easily be incorporated into a conventional radiation therapy system.